Bone fractures are sometimes fixated or stabilized using plates attached to the fractured bone by means of surgical nails or screws. This procedure generally works well for most patients. However, some patients have weak or brittle bones, for instance osteoporotic patients. In such patients, surgical nails or screws can often not be used to attach the plates onto the fractured bones. Hence, alternative procedures are needed for internal fixation of fractured bones in osteoporotic patients and other patients suffering from weak or brittle bones.
A common alternative to surgical nails or screws is cerclage, which is an orthopedic procedure in which the ends of an oblique bone fracture are bound together with wire loops or metal or plastic bands, in combination with an intramedullary pin, to hold them in position until the fracture has healed. The wire or band is generally very thin and may be cumbersome to handle for the surgeon. Furthermore, the wire or band needs to be held tight against the fractured bone in order to prevent any movement between the intramedullary pin and the bone and/or between the fractured bone parts. However, it is not uncommon, when tightening the wire or band, to unintentionally break the wire or band.
Another problem with the wires or bands used in cerclage procedures is that they effectively restrict microcirculation in the periosteum of the fractured bone. U.S. Pat. No. 4,146,022 discloses implants that can be used together with metal wires for internal fixation of bone fractures. Each implant is essentially a stainless steel cylindrical body having four sharp point at one end to be inserted into the bone tissue (cortex of the bone). A circular axial bore extends through the cylindrical body and a diametrical groove is present across the other end of the cylindrical body. A metal wire is then wrapped around the bone and positioned in the respective grooves in the top of each implant. The wire loop is tightened and will be elevated from the bone surface by the implants.
The implants of U.S. Pat. No. 4,146,022 are still marred by the problems of handling the metal wire and tightening it around the bone without breaking the metal wire. A further shortcoming of the implants is that a second surgical procedure is needed after bone healing in order to remove the implants and the wire loops.
Thus, there is a need for a medical device that solves at least some of the shortcomings of prior art technology.